Wire dispensing apparatus



April 1961 M. c. EANS, JR 2,981,491

WIRE DISPENSING APPARATUS INVENTOR: MARVIN C. EANS,JR.

HISYATTORN Y.

UnitedStates ateflt O 2,981,491 WIRE DISPENSING APPARATUS Marvin C. Eans, Jr., Owensboro, Ky., assignor to General Electric Company, a corporation of New York Filed Dec. 13, 1957, Ser. No. 702,592 7 6 Claims. (Cl. 242-45) This invention relates to a novel wire dispensing de- Ice particularly suitable for use in the manufacture of the wound wire type of grid electrode for electron dislateral wire to avoid breaking it. It is also important to keep the tension of the lateral wire uniform during the winding process to avoid later distortion of the shape of the electrode. The tension regulating problem is com-, plicated by the fact that feeding of the lateral wire to the winding apparatus is not continuous but is periodi cally interrupted by a brake engageable with the wire which holds the wire stationary long enough to permit separation from the running portion of the wire of that portion wound into a grid. The'result of this intermit A tent braking action is to periodically slacken the running portion of the wire between the brake and the wire supply, Which slack must be removed before the tension of the wire can be restored to the desired value.

A principal object of the present invention is to pro vide improved wire dispensing apparatus partticularly suitable for use with grid winding apparatus and having improved means for maintaining uniform tension of the dispensed wire.

Another object is to provide apparatus for dispensing flexible linear material through a brake adapted to intermittently engage the linear material and stop its movement, said dispensing apparatus having improved means for eliminating slack in the linear material produced by the application of the brake.

These and other objects will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

Fig. 1 is a perspective view of dispensing apparatus constructed according to the invention; and

Fig. 2 is a schema'ic diagram of an electrical control circuit associated with the apparatus of Fig. 1.

According to the invention, the wire or other linear material is dispensed from a supply spool which is driven bya variable speed and reversible motor. Speed and direction of rotation of the supply spool is determined by a motor control responsive to tension in the linear material dispensed. The spool is driven in the pay-out direction at a rate sufficient to satisfy demand for linear material yet maintained desired tension, and upon braking of the linearmaterial at a point removed from the spool, the tension responsive motor control operates to reverse the motor so as to take up any slack and restore desired tension to the linear material before further material is dispensed.

Referring to the drawing, 2 is a rotatable mandrel on which are supported and along which are fed in spaced parallel relation a pair of rods 3 onto which lateral wire 4 is wound to form electrodes. The Wire is fed to the mandrel 2 through a guide 5 across a series of pulleys 6, 8, 10 from a spool 12 rotatably mounted in a frame 14 and arranged to be driven by an electric motor 16. Between the guide 5 and the adjacent pulley 6 is a wire braking device 18 including a pair of jaws (not shown) between which the running portion of the wire passes, and which can be forced together, for example by cams (not shown), to prevent movement of wire therethrough as desired to break off or otherwise separate the running portion of the wire from that already wound into a complete grid on the mandrel.

In accordance with the invention, provision is made to maintain a uniform desired tension in the wire during the grid winding cycle, both during the time the wire is being paid out from the spool and drawn onto the mandrel with the jaws of brake 18 open to permit free passage of the wire therethrough, as well as when the brake jaws are closed and movement of the wire through the brake is stopped. To this end, motor 16 is of a variable speed and reversible type, and an associated motor control arrangement is provided which is a particular feature of the invention and will now be described in detail.

The pulley 10 is mounted on one end of an arm 20 pivotally supported for movement with the rotor 24 (best shown in Fig. 2) of a toroidally shaped autotransformer 26 mounted on the frame 14. The arm 20 is urged against a stop 28 by a tension spring 30 connected between an extension of the arm 20 and a pin 32 secured to the frame 14.

As indicated in Fig. 2, the motor 16 is shown by way of example as of the capacitor start induction motor type, the rotor 40 of which is drivingly connected to the wire supply spool 12. The motor has a pair of stator windings 42, 44 one of which 42 is connected in series with a starting capacitor 46 across the terminals 48, 50 of an alternating voltage source. To permit variation in speed and in direction of rotation of the motor the other stator winding 44 is supplied with a variable voltage from the autotransformer 26. One fixed end tap 54 and an intermediate fixed tap 56 of autotransformer 26 are connected to respective terminals 50, 48 of the alternating voltage source The movable tap 58 of the autotransformer, mounted on rotor 24, is connected to one side of the primary of a voltage step-up transformer 60, the other side of the transformer primary being connected to terminal 48. Across the secondary of the transformer, one end of which is connec ed to terminal 48, is con nected a potentiometer 62 the movable tap of which is connected to one side of stator winding 44. The other side of stator winding 44 is connected to terminal 48.

With this arrangement it may be seen that movement of the movable tap 58 of the autotransformer varies the amplitude of the voltage supplied to stator winding 44 and hence varies the motor speed. Also movement of the tap 58 from one side of the intermediate tap 56 to the other reverses the phase of the voltage applied to stator winding 44 and hence reverses the direction of rotation of the motor 16. The potentiometer 62 permits adjustment of the maximum speed of the motor, while the voltage gain provided by the step-up transformer 60 increases the sensitivity with which movement of the movable tap 58 of the autotransformer varies the motor speed.

In the operation of the wire dispensing device, rotation of the mandrel draws wire from the spool 12, and the inertia of the spool increases the tension in the wire and pivots the pulley arm 20 in a direction away from the stop 28. This moves the movable tap 58 of the autotransformer 26 in a direction away from the intermediate fixed tap 56 and toward the fixed tap 54, supplying an increased voltage to stator winding 44 of motor 16 and causing the motor to drive the spool in the wire pay-out direction. As the lever 20 moves further away from stop 28, the motor voltage is increased further by the autotransformer 26, further increasing the motor speed until the demand of the mandrel for wire is met and wire is being payed out from the spool at the same rate as the wire is being taken up by the mandrel. Under these conditions the force exerted by the spring is such as to maintain the wire tension at the desired value.

When the brake 18 is closed, interrupting movement of the wire therethrough, the continued rotation of the spool 12 in the pay-out direction slackens the wire and permits the arm 24) to move toward the stop 28; This in turn moves the movable tap 58 of the au'totransformer to a position of coincidence with the intermediate fixed t p 56, reducing to zero the voltage supplied to the stator winding 44 and thereby stopping the motor. If all of the slack in the wire is not taken up by movement of the pulley arm 20 to a position such that the movable tap 58coincides with the intermediate tap 56 and the motor stops, then the pulley arm 29 will continue to be further moved toward the stop 28 by the spring 30 sufliciently to shift the movable tap 58 to a point on the autotransformer winding on the opposite side of intermediate fixed tap 56 from fixed end tap 54. This reverses the phase of the voltage supplied to the motor stator winding 44, causing the motor 16 to run in the reverse direction and thereby drive the spool 12 in the take-up direction until all the slack is removed from the wire. The motor thereafter continues to run in the reverse direction until the continued take-up of the wire onto the spool 12 tensions the wire enough to pull the pulley arm 20 down away from the stop 28 far enough to return the movable tap 58 to coincidence with tap 56 and thereby stop the motor. Thus the desired wire tension is restored before the brake jaws open and winding of the next grid commences.

Thus it may be seen that a Wire dispensing device constructed according to my invention preserves desired wire tension at all times during a grid winding, automatically removing slack resulting from closing of the brake jaws so that the winding of each successive grid always begins with the desired tension on the wire. The dispensing device also insures immediate automatic shutofl of the motor should the wire accidentally break during operation of the dispenser. Also the wire dispenser is small, rugged, relatively inexpensive, and capable of reliable operation for long periods, as required for volume production, without requiring repair or adjustment. 7

It will be appreciated by those skilled in the art that the invention may be carried out in various ways and may take various forms and embodiments other than those illustrative embodiments heretofore described. It is to be understood, therefore, that the scope of the invention is not limited by the details of the foregoing description, but will be defined in the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In apparatus for paying out linear material through a brake engageable with the linear material and adapted to intermittently interrupt the flow of said linear material, a rotatable spool from which the linear material is adapted to be payed out, an autotransformer having a fixed end tap and a fixed intermediate tap and a tap movable relative to the two fixed taps, a voltage source connected be tween the intermediate tap and the fixed end tap of the antotransformer, a spool drive motor variable in speed responsive to voltage magnitude and variable in direction responsive to reversal in voltage phase, means connecting said motor in circuit between the movable tap and said intermediate tap ofthe autotransformer for running of the motor in the spool pay-out direction when the movable tap is between said intermediate tap and said fixed end tap and for running the motor in the spool take-up direction when the movable tap is on the opposite side of the intermediate tap from the fixed end tap, a tension sensing device engageable with the linear material dispensed from the spool, means connecting the tension sensing device to the movable tap of the autotransformer for moving the movable tap toward said fixed end tap responsive to increasing tension of said linear material, and a spring urging the movable tap away from the fixed end tap of the autotranstormer.

2. In apparatus for dispensing linear material, a rotatable spool from which the linear material is adapted to be payed out, an electric motor for driving the spool, said motor being variable in speed responsive to supply voltage magnitude and reversible in direction of rotation responsive to reversal in supply voltage phase, motor voltage supply means including an autotransformer provided with a movable tap having a reference position corresponding to zero output voltage, said movable tap being movable from the reference position in one direction to develop an output voltage of one phase having a magnitude proportional to displacement of said movable tap from said reference position, said movable tap being movable from said reference position in the other direction to develop an output voltage of the opposite phase having a magnitude proportional to displacement of said movable tap from said reference position, means including a voltage step up transformer connecting the output of said motor voltage supply means to said motor, and means responsive to tension of the linear material for moving said movable tap.

3. In apparatus for dispensing linear material, a rotatable spool from which the linear material is adapted to be payed out, an electric motor for driving the spool, said motor being variable in speed responsive to supply voltage magnitude and reversible in direction of rotation responsive to reversal in supply voltage phase, motor voltage supply means including an autotransformer provided with a movable tap having a reference position corresponding to zero output voltage, said movable tap being movable from the reference position in one direction to develop an output voltage of one phase having a magnitude proportional to displacement of said movable tap from said reference position, said movable tap being movable from said reference position in the other direction to develop an output voltage of the opposite phase having a magnitude proportional to displacement of said movable tap from said reference position, a voltage step up transformer fed by the output of said motor voltage supply means, a potentiometer connected between the output of said step up transformer and said motor, and means responsive to tension of the linear material for moving said movable tap 4. In apparatus for paying out linear material from a rotatable supply spool, a variable transformer having a pair of fixed taps and a tap movable relative to the two fixed taps, a voltage source connected between the fixed taps of the variable transformer, an electric motor for driving the spool, said motor being variable in speed responsive to voltage magnitude and variable in direction responsive toreversal in voltage phase, means connecting said motor in circuit between the movable tap and one fixed tap of the variable transformer for running of the motor in the spool pay-out direction when the movable tap is between said one fixed tap and the other fixed tap and for running the motor in the spool take-up direction when the movable tap is on the opposite side of said one fixed tap from said other fixed tap, a tension sensing device engageable with the linear material dispensed from the spool, means connecting the tension sensing device to the movable tap of the variable transformer for moving the movable tap toward said other fixed tap responsive to increasing tension of said linear material, and a spring urging the movable tap away from said other fixed tap of the transformer.

5. In apparatus for dispensing linear material, an electric motor for driving a spool from which the linear material is adapted to be paid out, said motor being variable in speed responsive to supply voltage magnitude and reversible in direction of rotation responsive to reversal of the phase of supply voltage, motor voltage supply means including a variable transformer provided with a movable tap having a reference position corresponding to zero output voltage, said movable tap being movable from the reference position in one direction to develop an output voltage of one phase and having a magnitude proportional to displacement of said movable tap from said reference position, said movable tap being movable from said reference position in the other direction to develop an output voltage of'the opposite phase and having a magnitude proportional to displacement of said movable tap from said reference position, means connecting the output of said motor voltage supply means to said motor, and means responsive to tension of the linear material for moving said movable tap.

6. Apparatus for dispensing linear material from a rotatable spool, comprising a variable transformer having a pair of fixed taps and a tap movable relative to the fixed taps, the fixed taps being adapted to be connected to a source of alternating voltage, a motor for driving the spool, said motor being variable in direction in response to reversal in voltage phase, means connecting said motor between the movable tap and one fixed tap of said variable transformer for running the motor in a predetermined direction when the movable tap is between said one fixed tap and the other fixed tap and for running the motor in the opposite direction when the movable tap is on the side of said one fixed tap opposite said other fixed tap, a tension-sensing device engageable with the linear material and adapted to move the movable tap toward said other fixed tap in response to alterations in tension of said linear material, and means urging the movable tap away from said other fixed tap.

Zschach July 2, 1935 Turner et al. July 22, 1958 

